Purpose and characteristics of the fan

   Model 9-19 centrifugal fan is generally used for forging furnace and high pressure forced ventilation, widely used for materiel delivery and suitable to delivery air and gas of non-corrosion, non self-burn and free of viscous material. The temperature of the delivered medium shall normally not exceed 250℃ (not exceed 300℃ maximum), the dust contained in the medium and hard-fine particle shall not be bigger than 150mg/m3. This series of fans in addition to the above characteristics, but also has high efficiency, low noise, large flow adjustment range, flat perbance curve and so on. Fan three high degree of versatility, good versatility, wide range of application.

Type of fan

   1. The fan is made as a single suction and its driving is A type. There are more than 20 types of fan numbers which are 3、3.15、4、4.5、5、5.6、6.3、7.1、8、9、10、11.2、12、12.5、14、16、18、and 20.

2. The fan can be made of 2 types of rotation i.e, right and left. Viewing from one end of the motor, it is called as clock-wise fan if the impeller rotates clock-wise, shown as “right”, On the contrary, it is called as counter-clock-wise fan if the impeller rotates counter-clock-wise, shown as “left”.

3. The outlet b of the fan can be expressed from the outlet angle of the casing. It can be made 7 kinds of angles which are 0°, 45°,90°, 135°,180°,225°, 270°，from both “Right” and “left”.

4. There are 4 driving modes: A,B, C, D:

A—Shaft disc of fan is installed on motor shaft by keyway, i.e. motor directly connecting;   

B—Cantilever bearing unit, belt driving, pulley is in the middle of two bearings;

C—Cantilever bearing unit, belt driving, but the pulley is outside the bearing;

D—Cantilever bearing unit, coupling directly driving.

Structure of the fan

№3-7.1 fan mainly consists of impeller, casing and inlet. №7.1- above fan mainly consists of impeller, casing inlet and Driving unit.

Casing: to be welded into a volute with normal steel plate.

Impeller: The fan has 12 forward-curved blades. The maximum circumference speed of impeller diffuser shall not exceed 140m/s. The impeller, after being shaped, shall be balanced statically and dynamicaly and thus it guarantees a smooth operation.

Inlet: to be integrated into a convergent streamlined structure and bolted on the front cover.

Driving unit—it consists of shaft, bearing box, rolling bearing, belt pulley or coupling.

See the attached drawing for installation and overall dimension.

Perbance and selection of the fan

Perbance of the fan:The perbance of the fan is expressed by the beters of fan flow, full pressure, spindle speed, shaft power and so on. Perbance curve and the perbance of the perbance given in the table. Blower perbance:20 degrees Celsius, atmospheric pressure is 101325 Pascal,Gas density is 1.2Kg/m³,calculation and calculation of air medium. (Other designs are similar to the use of beters.)

The perbance of both the selection curve and the perbance table refers to the perbance of adjusting the blade to a full 0 degree centigrade. When ordering the perbance table shall prevail. Fan perbance test total pressure value of 5% of the total pressure deviation is less than design value.

Such as fan using condition does not accord with the above, the perbance shall be carried out according to the related bula conversion.

When excessive or insufficient flow of processing. When use, often occur the phenomenon of excessive or insufficient flow, produce a lot of reasons for this phenomenon, if it is in use process flow occurs when small phenomenon, is mainly due to the resistance of pipe network. If it is in use process, after a long time to reduce gradually, mainly due to network congestion.

After the fan is a new installation, a bal operation occurs when the flow phenomenon of excessive or insufficient reason mainly has the following points:

1. The actual value and calculating value difference is too large in the resistance of pipelines.

By the general network characteristic equation: P = Kq², type of K - drag coefficient.

If the actual value K is less than the calculated value K, increases the flow, if the actual value K is greater than the calculated value K, the flow decreases.

2. when the choice is not the fan itself fully considering the influence of the pressure deviation of δP, when the fan actual total pressure for positive deviation, then the flow; Negative deviation, the flow rate decreases.

Began bal operation after fan is a new installation, or in use process flow is too big or too small, one of the following bs can be used to eliminate it.

Make use of the fan speed adjusting flow increase or decrease.

Using the new high or low pressure switch to increase or decrease in flow rate of fan.

Change the pipeline resistance coefficient K to change traffic.

At this time to try to change the network reduce drag coefficient to increase traffic, also can increase the fan rotation speed and changing the high pressure fan, but speed shall not be greater than the maximum speed perbance table.

The basis and the shape of the fan

9-19 type fan shape and see the appended drawings

Installation and operation of the fan

 Before installation: Check all components of the fan to see weather any thing is missed; weather the impeller rotates in the same direction as the casing; weather all components are connected tightly and weather the impeller rotates freely.

During installation: Pay attention to check the casing and any tools or goods should not be dropped and remained inside the casing. The connecting face between the support of the fan and the foundation or between pads and foundation should be tight. Adjusting should be made to joint the fan with foundation surface and to connect the fan with suction, discharge duct naturally. Forced assembling, especially, applying weight of pipes on any components of the fan isimpermissible. Also, attention shall be paid to the horizontality of the fan.

Requirement of installation:

1. Install the fan according to the b and sizes shown on the drawing. To insure high efficiency, radial and axial bances between inlet and impeller must be guaranteed.

2. After installation, turn, with a little force, the driving rotor to see if it is over tight or touched with stationary components.

3. Commission Can only be carried out after the unit is through the final inspection.

4. In order to prevent the motor being burnt out due to overloading, the fan can only be started up and tested without loading. If the case is ok, increase the load step by step until the rated operating condition is reached. Control the current strictly during operation to prevent it exceeding the rated value.

Operation of the fan:

  Before starting-up, the following preparations shall be made:

1) Close the valve of suction pipe and open a little the valve on discharge pipe.

2) Check the rotating and non –rotating parts to prevent colliding and friction.

3) After the fan is started-up and the normal speed is reached, check the bearing temperature is normal or not during the operation. If there is no special requirement for bearing temperature, the temperature rise of the bearing shall not exceed 40℃ of surrounding temperature. The value of even root vibration speed of the bearing shall comply with the following rules: rigid support(support is fixed on the foundation) Vrms≤4.6mm/s; flexible support(be set onfoundation or floor through absorber) Vrms≤7.1mm/s. In case that severe vibration, colliding, quick rise of bearing temperature and other abnormal phenomena are found, stop the fan immediaby.

Maintenance of the fan

1. Don’t allow fan with trouble running.

2. Don’t freely change the maintenance person, specific person operating and repair the fan is preferred.

3. Regularly remove dust, contamination and the foreign materials and prevent rust .

4. Maintenance can be carried out during shut down of fan to assure operators safety.

5. When the fan is repaired, the motor switch must be monitored or locked.

6. Inspect the thermometer and oil indicator regularly.

7. During the star-up, shut-down or operation of the fan, if some abnormal thing happens, inspections shall be carried out immediaby; if it is small failure, the reason shall be checked out and eliminated, if it is a big failure, the fan shall be stopped and inspection and maintenance shall be made immediaby.

8. Except replacing the lubricant after overall, replace the lubricating oil periodically.